Fuel injection valve assembly for internal combustion engines

Abstract

An injection valve assembly for spraying fuel into a diesel engine by receiving accurately metered charges of the fuel under pressure from an engine-driven jerk pump. The fuel inlet of the valve assembly communicates via a check valve with a storage chamber, where each incoming charge of pressurized fuel is stored temporarily. The fuel outlet of the valve assembly, in communication with the storage chamber, is normally closed by a spring-biased needle valve member. Upon full accumulation of each fuel charge in the storage chamber the check valve automatically closes the fuel inlet thereby causing the needle valve member to be displaced under the fuel pressure against the bias of the spring and hence to open the fuel outlet. Another embodiment employs two needle valve members, one for the on-off control of communication between the storage chamber and the fuel outlet, and the other for the on-off control of the fuel outlet.

What is claimed is: 
     
       1. A fuel injection valve assembly for an internal combustion engine, comprising: (a) a body having formed therein: (1) a fuel inlet for admitting successive charges of pressurized fuel;   (2) a spring chamber in constant communication with the fuel inlet;   (3) a storage chamber for storing each incoming charge of pressurized fuel; and   (4) a fuel outlet for discharging in the form of droplets the pressurized fuel fed from the storage chamber;     (b) spring means in the spring chamber,   (c) needle valve means mounted within the body for reciprocable motion between a first and a second position and extending between the spring chamber and the fuel outlet through the storage chamber and normally held under the bias of the spring means in the first position to close the fuel outlet, the needle valve means having: (1) an inlet passageway for the introduction of the pressurized fuel from the fuel inlet into the storage chamber; and   (2) means adapted to be acted upon at least by the pressurized fuel stored in the storage chamber, the needle valve means when so acted upon being moved from the first to the second position against the bias of the spring means for opening the fuel outlet; and     (d) a check valve for blocking the inlet passageway after each charge of pressurized fuel is introduced into the storage chamber from the fuel inlet.   
     
     
       2. The fuel injection valve assembly as recited in claim 1, wherein the needle valve means comprises a single needle valve member. 
     
     
       3. The fuel injection valve assembly as recited in claim 2, wherein the body has further formed therein a valve lift chamber disposed between and communicating with the storage chamber and the fuel outlet, and wherein the needle valve member has a surface adapted to be acted upon by the pressurized fuel in the valve lift chamber for movement from the first to the second position. 
     
     
       4. The fuel injection valve assembly as recited in claim 1, wherein the body has further formed therein: (a) an outlet passageway for the delivery of the pressurized fuel from the storage chamber to the fuel outlet, the outlet passageway being closed by the needle valve means when the latter is in the first position; and   (b) a valve lift chamber in constant communication with the outlet passageway, the needle valve means being adapted to be acted upon by the pressurized fuel in the valve lift chamber for movement from the first to the second position against the bias of the spring means.   
     
     
       5. The fuel injection valve assembly as recited in claim 4, wherein the needle valve means comprises: (a) a first needle valve member extending from the fuel inlet into the storage chamber and having the inlet passageway formed therein, the first needle valve member closing the outlet passageway when in the first position; and   (b) a second needle valve member for opening and closing the fuel outlet, the second needle valve member extending through the valve lift chamber and being adapted to be moved from the first to the second position by the pressurized fuel contained therein.   
     
     
       6. In combination with an engine-driven jerk pump, a fuel injection valve assembly comprising: (a) a body having formed therein: (1) a fuel outlet for admitting successive metered charges of pressurized fuel from the jerk pump;   (2) a spring chamber in constant communication with the fuel inlet;   (3) a storage chamber for temporarily storing each incoming charge of pressurized fuel; and   (4) a fuel outlet in communication with the storage chamber for discharging the pressurized fuel in the form of droplets;     (b) a spring in the spring chamber;   (c) a needle valve member slidably mounted within the body for reciprocable motion between a first and a second position and extending between the spring chamber and the fuel outlet through the storage chamber, the needle valve member being normally retained by the spring in the first position for closing the fuel outlet, the needle valve member having: (1) an inlet passageway for the introduction of the pressurized fuel from the fuel inlet into the storage chamber; and   (2) means adapted to be acted upon at least by the pressurized fuel in the storage chamber, the needle valve member when so acted upon being moved from the first to the second position against the bias of the spring means for opening the fuel outlet; and     (d) a check valve for blocking the inlet passageway after each charge of pressurized fuel is introduced into the storage chamber from the fuel inlet.   
     
     
       7. The fuel injection valve assembly as recited in claim 6, wherein the body has further formed therein a valve lift chamber in constant communication with the storage chamber, and wherein the needle valve member is adapted to be acted upon by the pressurized fuel in the valve lift chamber for movement from the first to the second position. 
     
     
       8. In combination with an engine-driven jerk pump, a fuel injection valve assembly comprising: (a) a body having formed therein: (1) a fuel inlet for admitting successive metered charges of pressurized fuel from the jerk pump;   (2) a first and a second spring chamber, the first of which is in constant communication with the fuel inlet;   (3) a storage chamber for temporarily storing each incoming charge of pressurized fuel, the storage chamber having an exit port defined by a valve seat;   (4) a valve lift chamber in communication with the exit port of the storage chamber; and   (5) a fuel outlet in communication with the exit port of the storage chamber for discharging the pressurized fuel in the form of droplets;     (b) a first and a second spring mounted in the first and the second spring chamber respectively;   (c) a first needle valve member reciprocably extending between the first spring chamber and the storage chamber and having formed therein an inlet passageway for the introduction of the pressurized fuel from the fuel inlet into the storage chamber, the first needle valve member being biased by the first spring into engagement with the valve seat so as to be acted upon in a direction away from the valve seat by the pressurized fuel in the storage chamber and in the valve lift chamber;   (d) a second needle valve member reciprocably extending between the second spring chamber and the fuel outlet through the valve lift chamber and normally closing the fuel outlet under the bias of the second spring, the second needle valve member being adapted to be acted upon in a direction away from the fuel outlet by the pressurized fuel in the valve lift chamber; and   (e) a check valve for blocking the inlet passageway after each charge of pressurized fuel is introduced into the storage chamber from the fuel inlet.   
     
     
       9. The fuel injection valve assembly as recited in claim 8, wherein the first and the second spring chambers are in constant communication with the fuel inlet.